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Urban wilderness has gradually emerged as a hot spot for urban ecological research due to its crucial role in maintaining urban ecosystem services and protecting biodiversity. Compared to natural areas, urban wildnesss are more susceptible to invasions by alien species, which pose a threat to the functionality of the urban ecosystem. Currently, our understanding of biodiversity within various types of urban wilderness is not comprehensive, and the laws governing biodiversity changes due to alien species invasions remain unclear. This study focuses on an abandoned grassland community on a campus in northern China, which has been invaded by the alien weed Gaura parviflora . The study measured the characteristics of the aboveground community and the soil seed bank, comparing and analyzing species composition, plant/seed density, species diversity, and similarity at different levels of invasion (uninvaded, moderately invaded, severely invaded). The findings indicate that the uninvaded abandoned grassland community is rich in species (with 32 species) and has significant recovery potential (with an average seed density of 11,671 seeds per square meter). The community harbors multiple alien invasive species both aboveground and within the soil seed bank, and its succession process is influenced by biological invasions and human disturbances. The invasion by G. parviflora alters the species composition of both the aboveground community and the soil seed bank, resulting in a significant increase in plant density within the aboveground community. Its impact on the soil seed bank varies with soil depth, leading to a notable decrease in seed density in the 0–5 cm layer compared to the 5–10 cm and 10–15 cm layers; while the Shannon-Wiener biodiversity index for the 0–5 cm and 10–15 cm layers is lower than that of the uninvaded and severely invaded plots. This study reveals that the campus abandoned grassland community faces a high risk of biological invasion, and the invasion by G. parviflora has a more significant impact on the soil seed bank than on the aboveground community, which could lead to substantial changes in community species composition and a loss of biodiversity in the soil seed bank. It is therefore strongly recommended that greater attention be given to the impact of biological invasions on seed banks within the management of campus wild ecosystems.

In this study, three Li-free polyanion vanadium sulfates containing Na/K alkali metals were successfully synthesized by a facile solid-state method at moderate temperature. To improve the electronic conductivity, these three vanadium sulfate samples were mixed with carbon black SuperP by ball milling. These composites were characterized using XRD, IR, Raman, UV–vis diffuse reflectance, and FESEM. Moreover, the NaV(SO4)2/C, Na3V(SO4)3/C, and K2VO(SO4)2/C composites were investigated as cathode materials for lithium-ion batteries (LIBs) for the first time. There are continuous ion transport channels in all three compounds, which tolerate reversible insertion-extraction of lithium ions. Benefiting from the two-electronic reaction of V4+/V3+ and V3+/V2+ redox pairs, Na3V(SO4)3/C and K2VO(SO4)2/C deliver discharge specific capacities of 120 mAh⋅g−1, while NaV(SO4)2/C displays a higher specific capacity of 200 mAh⋅g−1 in the first cycle. However, their rate performance and cyclic stability are poor, which may be attributed to the solubility of sulfate in electrolyte.

The escalating challenge of solid waste disposal necessitates innovative recycling strategies. This study aims to constructed technosols from bulk solid wastes (fly ash, straw and sewage sludge) for the dual purpose of sustainable waste management and the rehabilitation of degraded land. Following a 150-day incubation period, six resulting technosols were systematically evaluated for aggregate stability, bacterial community structure, and biological safety to assess their viability as functional soil materials. All constructed technosols had a pH of 7.44–7.71 and were enriched in soil organic matter, nitrogen, and phosphorus. Aggregate stability (R0.25: 46.6–64.0%) surpassed that of typical Chinese soils. Bacterial analysis revealed a stable consortium of 165 core genera, accounting for 92.93–98.11% of the total relative abundance, and were dominated by six phyla (Proteobacteria, Bacteroidota, Planctomycetota, Gemmatimonadota, Firmicutes, Actinobacteriota). The addition of straw modulated phylum structure, elevating Bacteroidota and reducing Proteobacteria. The bacterial communities exhibited clear functional hierarchy at class and order levels, with dominant groups forming a complementary carbon–nitrogen–phosphorus cycling network. Functional prediction further indicated distinct differentiation in carbon and nitrogen metabolic pathways. The technosols were non-phytotoxic and significantly enhanced the growth of Portulaca oleracea, increasing plant height (4.9–86.7%), dry weight per plant (67.3–605.4%), and SPAD values (8.1–15.9%), respectively. This study provides a sustainable strategy for repurposing solid wastes into functional technosols, aligning with circular economy principles and offering a viable solution for the ecological restoration of degraded lands such as mining areas.

Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

Broadening the light absorption range and suppressing the carrier complexation are the two keys to enhance the photocatalytic activity. In this work, a novel two-dimensional (2D) photocatalyst was successfully prepared by modified hydrothermal method and applied in tetracycline (TC) degradation. The degradation rate of CD(Cu)-Ni-MOL for TC reached 93.5% within 60 min under the visible light condition. The improved photocatalytic performance of CD(Cu)-Ni-MOL was attributed to the constructed 2D layered structure and the special properties of CD(Cu). The doped Cu in carbon dots (CDs) exhibited excellent photocatalytic performance among the elements of Cu, Zn, Ni, Co and Fe. The order of photocatalytic performance improvement was Cu > Zn > Ni > Co > Fe. In addition, a possible degradation pathway for TC was proposed. This work confirms the great potential of CD(Cu)-Ni-MOL as a highly efficient photocatalyst in removing tetracycline pollutants in water.

Wetlands are an important carbon reservoir pool in terrestrial ecosystems. Light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and dissolved organic carbon (DOC) were fractionated in sediment samples from the four wetlands (ZR: Zhaoniu River; ZRCW: Zhaoniu River Constructed Wetland; XR: Xinxue River; XRCW: Xinxue River Constructed Wetland). Organic carbon (OC) from rivers and coasts of China were retrieved and statistically analyzed. At regional scale, HFOC stably dominates the deposition of OC (95.4%), whereas DOC and LFOC in ZR is significantly higher than in ZRCW. Concentration of DOC is significantly higher in XRCW (30.37 mg/l) than that in XR (13.59 mg/l). DOC and HFOC notably distinguish between two sampling campaigns, and the deposition of carbon fractions are limited by low nitrogen input. At the national scale, OC attains the maximum of 2.29% at precipitation of 800 mm. OC has no significant difference among the three climate zones but significantly higher in river sediments than in coasts. Coastal OC increases from Bohai Sea (0.52%) to South Sea (0.70%) with a decrease in latitude. This study summarizes the factors affecting organic carbon storage in regional and national scale, and have constructive implications for carbon assessment, modelling, and management.

The Yellow River Delta, an important area of reserved arable land resources in China, is faced with the problem of crop productivity being typically limited by low soil quality. Developing techniques that raised crop yield without environmental damage was critically needed. To date, the knowledge about the joint impacts of biochar (C) and phosphorus (P) addition on soil properties and maize production under different weather conditions in this area is seriously lacking. Consequently, a full factorial field experiment including three biochar intensities (0 (C0), 5 000 (C1), and 10 000 (C2) kg/ha), three phosphorus fertilisation levels (0 (P0), 60 (P1), and 120 (P2) kg P/ha), and their combinations was conducted in Binzhou, Shandong province of China from 2021 to 2022. Compared to 2022, the maize yield was dramatically reduced in 2021 (with a 35% mean decrease) due to excessive rainfall in the maize reproductive growth stage (P < 0.01). C addition caused greater proportions and contributions of dry matter and nutrient remobilisation from pre-anthesis vegetation organs to grain. Subsequently, maize yield was much more promoted in 2021 (23%) than in 2022 (5%) by adding C, in which the discrepancies between C1 and C2 were relatively small and insignificant. On the other hand, these corresponding effects of P and C × P were relatively modest. From the soil perspective, soil physical (hydraulic conductivity (Ks) and bulk density) and chemical properties (soil organic carbon, total N, and soil available N) were significantly improved by C addition (P < 0.01). More importantly, we detected negative interactions of C × P on soil available P and phosphorus activation coefficient (P < 0.01), as soil available P was lowered with more input of C and P together (particularly under P2 series). The two-year outcomes suggested that C addition could enhance maize growth and ensure crop yield stability. Still, the combined incorporation of this kind of C and P (especially for C2P2) was not recommended in the saline-alkali land. The present study delivered useful insight into the rational utilisation of C and P fertilisers in the Yellow River Delta.

Recurrent water level fluctuation and submergence of plants are common in riparian zones. Our study objectives were to test the independent and interactive effects of submergence level and fluctuation frequency on a globally important riparian invasive plant, Alternanthera philoxeroides. To this end, we conducted a greenhouse experiment, in which ramets of the plants, obtained from a wetland in China, were treated with four fluctuation frequencies (0, 3, 6, and 12 cycles over a 96-day experimental period) under three water levels (0, 10, and 30 cm). We found that effects of fluctuation frequency were non-significant, negative, and positive under water levels of 0, 10 and 30 cm, respectively. As fluctuation frequency increased, the effects of increasing water level decreased significantly. When water levels were high, A. philoxeroides allocated greater biomass to shoot production probably in order to elongate and escape from submergence. However, as fluctuation frequency increased, biomass investment in roots and leaves also increased, probably in order to maximize nutrient absorption and photosynthesis, respectively. These results suggest that water level fluctuation may alleviate the effects of submergence on A. philoxeroides. In addition, A. philoxeroides showed significant phenotypic plasticity, adjusting its functional traits, such as number of nodes and leaves per stem, as well as stem diameter and pith cavity diameter, according to recurrent water level fluctuation. We conclude that A. philoxeroides may perform better in shallow water zones under conditions of disturbance that include recurrent water level fluctuation. This ability to adapt to disturbance likely promotes its growth and invasion in disturbed habitats.

Biological invasions are increasingly attracting the ecologists' attention. Invasive plants threaten the natural ecosystems not only by competing with the native plants, but also by altering the structure and function of soil microbial communities belowground. In this study, we studied the effects of the invasive plant Coreopsis grandiflora (C. grandiflora) on the functional diversity of soil microbial communities in Laoshan mountain in the province of Shandong, North of China. We sampled soil from plots that were invaded or not invaded by C. grandiflora. The functional diversity of microbial communities in the sampled soils was assessed by the Biolog procedure test. By the ANOVA analysis of average well color development (AWCD), Shannon index (H'), Shannon evenness (E), principle components analysis of the level physiological profiles (CLPP) and correlation analysis between the studied parameters, we found that the invasive species C. grandiflora enhanced the functional diversity of soil microbial communities where the habitat was invaded by the C. grandiflora. The study indicated thatthe successful invasive plants have profound effects on the function of soil microbial communities.

In view of the important role of vegetation in the integrity of structures and functions of coastal wetland ecosystems, the restoration of degraded coastal wetland vegetation has attracted increased attention. In this paper, the newborn coastal wetland in the Yellow River Delta (YRD) of China was selected to research the effect of salinity and oil exploitation on the germination of soil seed banks of three dominant vegetation communities. The germination experiment with three concentration gradients of NaCl and three concentration gradients of diesel treatments showed that there were 14 species present in the soil seed bank of the multi-species community: three species in the Phragmites australis community, and five species in the P. australis—Suaeda glauca community. The species in the seed bank of the three communities were much richer than the above-ground vegetation in this study. Soil salinity had a significant inhibitory effect on the seedling numbers of germinated species, the seedling density, and the species diversity of the soil seed banks, while the inhibitory effect of diesel was indistinctive under the designed concentrations. There existed significant interactions between the vegetation community type and soil salinity on the number of germinated species, the seedling density, and the Margalef index. Soil salinity is considered an important factor for wetland vegetation restoration in the YRD, but its effect had species-specific differences. Soil seed banks of the present three communities could be used to promote the restoration of degraded wetlands within certain soil salinity and oil concentration ranges.